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Re: Server-managed vs storage-managed backup/recovery?

From: Tim Gorman <>
Date: Mon, 28 Jun 2004 16:39:50 -0600
Message-ID: <>

Funny thing is, I've never trusted dbverify. :-) Too many false positives, even on "offline" datafiles. Different code base from the Oracle kernel ­ not comforting. After all, for all the false positives it throws, how do you know how many Śreal negativesą it might be missing?

Besides, using dbverify still leaves the archived redo logfiles "un-verified" against corruption, so you have to come up with some other home-grown kludge like verifying them using Log Miner or standby db or ALTER SYSTEM DUMP LOGFILE or some such. Life is too short to reinvent a well-made wheel...

I'm optimistic at being able to test and validate a "grand unified theory" of backup/recovery where RMAN is used either with mirror-splits or without mirror-splits, supporting both storage-managed storage as well as server-managed storage. Best of all worlds...

Thanks for the help!


on 6/28/04 2:01 PM, Hand, Michael T at wrote:

> Tim,
> John hit all of the major points for the hot-backup via mirror split
> justification. The one additional use we put to ours is a daily Dbverify.
> We started this process with an 8.0 database and I wasn't ready to trust
> RMAN at that point. It will be interesting to see how these two concepts
> integrate.
> Mike
> -----Original Message-----
> From: Tim Gorman []
> Sent: Monday, June 28, 2004 3:17 PM
> To:
> Subject: Re: Server-managed vs storage-managed backup/recovery?
> John,
> Thanks so much for the reply!
> I'm trying to find the middle-ground between RMAN and the mirror-split
> methods. Right now, my approach is to make use of the CATALOG command to
> register a mirror-split as a DATAFILECOPY and then back the DATAFILECOPY off
> to tape using the BACKUP DATAFILECOPY command. This would allow RMAN to
> check for corrupted blocks, thus achieving the best of both worlds, but I've
> got a lot of testing to do, and I was wondering if anyone had used this
> already?
> Thanks!
> -Tim
> on 6/24/04 3:37 PM, John Kanagaraj at wrote:

>> Tim,
>> We use the the 'split mirror' hot-backup for our large Apps database. The
>> main reasons are (a) Keep backup I/O off the 'live' copy (b) Keep a copy

> of
>> the Database 'on-disk' for immediate recovery should a disk disaster

> strike
>> on the live copy. (c) We don't have to really bother about the backup

> window
>> as long as one cycle doesn't step into the next. (d) Clones are simply a
>> matter of FTP and archive log application. [Of course, storage $$ isn't an
>> issue here, if you know what I mean!]
>> Hth,
>> John Kanagaraj

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Received on Mon Jun 28 2004 - 17:35:55 CDT

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